Intel 1.00 GHz YK80542KC0013M Benutzerhandbuch

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YK80542KC0013M
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Datasheet 
System Management Feature Specifications
controller continues to transmit data bytes until it terminates the sequence with a stop. All data 
bytes will result in an acknowledge from the Scratch EEPROM. If more than eight bytes are 
written, the internal address will “roll over” and the previous data will be overwritten. 
In 
‘S’ represents the SMBus start bit, ‘P’ represents a stop bit, ‘R’ 
represents a read, ‘W’ represents a write bit, ‘A’ represents an acknowledge, and ‘///’ represents a 
negative acknowledge. The shaded bits are transmitted by the processor information ROM or 
Scratch EEPROM and the bits that are not shaded are transmitted by the SMBus host controller. In 
the tables the data addresses indicate eight bits. The SMBus host controller should transmit eight 
bits, but as there are only 128 addresses, the most significant bit is a don’t care.
6.5
Thermal Sensing Device
The Itanium 2 processor’s thermal sensing device provides a means of acquiring thermal data from 
the processor. The accuracy of the thermal reading is expected to be better than ±3 °C. The thermal 
sensing device is composed of control logic, SMBus interface logic, a precision analog to digital 
converter, and a precision current source. The thermal sensing device drives a small current 
through a thermal diode located on the processor core and measures the voltage generated across 
the thermal diode by the current. With this information, the thermal sensing device computes a byte 
of temperature data. Software running on the processor or on a micro-controller can use the 
temperature data from the thermal sensing device to thermally manage the system. 
The thermal sensing device provides a register with a data byte (seven bits plus sign) which 
contains a value corresponding to the sampled output of the thermal diode in the Itanium 2 
processor core. The value of the byte read from the thermal sensor gives an accurate reading of 
processor core temperature at the time of the reading. This data can be used in conjunction with the 
upper temperature reference byte (provided in the processor information ROM) for thermal 
management purposes. The temperature data from the thermal sensor can be read out digitally 
using an SMBus read command (see 
). The thermal sensor detects when SMBus power 
is applied to the processor, and resets itself at power up. 
The thermal sensing device also contains alarm registers to store thermal reference threshold data. 
These values can be individually programmed on the thermal sensor. If the measured temperature 
equals or exceeds the alarm threshold value, the appropriate bit is set in the thermal sensing device 
status register, which is also brought out to the Itanium 2 processor system bus via the 
Table 6-5. Current Address Read SMBus Packet
S
Device 
Address
R
A
Data
///
P
1
7  bits
1
1
8 bits
1
1
Table 6-6. Random Address Read SMBus Packet
S
Device 
Address
W
A
Data 
Address
A
S
Device 
Address
R
A
Data
///
P
1
7  bits
1
1
8  bits
1
1
7 bits
1
1
8 bits
1
1
Table 6-7. Byte Write SMBus Packet
S
Device 
Address
W
A
Data 
Address
A
Data
A
P
1
7  bits
0
1
8  bits
1
8  bits
1
1